patch 8.0.0702: an error in a timer can make Vim unusable

Problem:    An error in a timer can make Vim unusable.
Solution:   Don't set the error flag or exception from a timer.  Stop a timer
            if it causes an error 3 out of 3 times.  Discard an exception
            caused inside a timer.
diff --git a/src/version.c b/src/version.c
index 42fb71d..70de1d4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    702,
+/**/
     701,
 /**/
     700,